What Causes Asthma?

Asthma is a problem in the airways due to multiple factors. The airways in a person with asthma are very sensitive and react to many things, which are referred to as "triggers." Coming into contact with these triggers often produces asthma symptoms.

There are many kinds of asthma triggers. Reactions are different for each person and vary from time to time. Some people have many triggers while others have none that they can identify. One of the most important aspects of asthma control is avoiding triggers when possible.

*Note: While exertion may be an asthma trigger, exercise should not be avoided. With a good treatment plan, children (and adults) can exercise as long and as much as desired, except during an asthma attack.

How Is Asthma Diagnosed?

Doctors can use a number of tests to diagnose asthma. First, the doctor reviews your medical history, symptoms, and does a physical exam. Next, tests may be given to check the general condition of your lungs, including:

Chest X-ray in which a picture of the lungs is taken.

Pulmonary function test (spirometry): A test that measures how well the lungs can take in air and how well this air can be exhaled (lung function). The patient blows into a tube placed between the lips.

Peak expiratory flow: A test that measures the maximum speed that air can be exhaled from the lungs. The patient blows into a hand-held device called a peak flow meter.

Methacholine challenge test: A test used to see if the airways are sensitive to methacholine, an irritant that tightens the airways.

Other tests, such as allergy tests, blood tests, sinus X-rays and other imaging scans, and esophageal (throat) pH tests may also be ordered. These tests can help your doctor find out if other conditions are affecting your asthma symptoms.